1. Field of the Invention
This invention relates to image pickup apparatus, and more particularly to a body of image pickup apparatus having a mount surface for mounting a lens.
2. Description of the Related Art
To adjust the flange back of camera, or the distance from the reference surface (flange surface) at which the lens is attached to the body to the film plane, for the mount surface for attachment of the lens is fixed in position, the photographic lens may be provided with a relay lens as arranged to be axially movable. Such an adjusting method was ever used in the past.
However, because the use of this method led to the necessity of incorporating the movable relay lens into the photographic lens system, if any of the interchangeable lenses available in the market which had generally no movable relay lens was used, such flange back adjustment could not be carried out. In order to make such flange back adjustment possible even with the use of such commonly available interchangeable lens, the mount surface at which the interchangeable lens is attached to the camera body must be made axially movable.
According to the prior art, therefore, a plurality of washers of different thickness were prepared. And, the flange back adjustment was carried out by the method of trial and error. In more detail, one of such washers was selected to be inserted into between the mount surface-constituting member and the camera body. Then, this member was fastened to the camera body. If the video signals obtained from such camera were found by means of a monitor or the like to have a defect as attributed to the washer of inappropriate thickness, the member of the mount surface should be disassembled from the camera body, and, after the washer was exchanged by another one whose thickness was different from that of the former, reassembled thereto. Besides the flange back adjustment, the angle of orientation of the mount surface with respect to the camera body was made adjusted in a similar way.
The above-described method of exchanging the washers when applied to not only the adjustment of the axial position of the mount surface but also the adjustment of the angle of its orientation had problems that the disassembling followed by the reassembling of the mount member to the camera body had to be repeated usually a large number of times until a satisfactory result was attained, and that as the degree of tolerance on the angle of orientation of the mount surface increased, many kinds of washers were necessarily prepared.